/* Copyright 2013 Google Inc. All Rights Reserved.
Distributed under MIT license.
See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
*/
/* Glyph manipulation */
#include "./glyph.h"
#include <stdlib.h>
#include <limits>
#include "./buffer.h"
#include "./store_bytes.h"
namespace woff2 {
static const int32_t kFLAG_ONCURVE = 1;
static const int32_t kFLAG_XSHORT = 1 << 1;
static const int32_t kFLAG_YSHORT = 1 << 2;
static const int32_t kFLAG_REPEAT = 1 << 3;
static const int32_t kFLAG_XREPEATSIGN = 1 << 4;
static const int32_t kFLAG_YREPEATSIGN = 1 << 5;
static const int32_t kFLAG_OVERLAP_SIMPLE = 1 << 6;
static const int32_t kFLAG_ARG_1_AND_2_ARE_WORDS = 1 << 0;
static const int32_t kFLAG_WE_HAVE_A_SCALE = 1 << 3;
static const int32_t kFLAG_MORE_COMPONENTS = 1 << 5;
static const int32_t kFLAG_WE_HAVE_AN_X_AND_Y_SCALE = 1 << 6;
static const int32_t kFLAG_WE_HAVE_A_TWO_BY_TWO = 1 << 7;
static const int32_t kFLAG_WE_HAVE_INSTRUCTIONS = 1 << 8;
bool ReadCompositeGlyphData(Buffer* buffer, Glyph* glyph) {
glyph->have_instructions = false;
glyph->composite_data = buffer->buffer() + buffer->offset();
size_t start_offset = buffer->offset();
uint16_t flags = kFLAG_MORE_COMPONENTS;
while (flags & kFLAG_MORE_COMPONENTS) {
if (!buffer->ReadU16(&flags)) {
return FONT_COMPRESSION_FAILURE();
}
glyph->have_instructions |= (flags & kFLAG_WE_HAVE_INSTRUCTIONS) != 0;
size_t arg_size = 2; // glyph index
if (flags & kFLAG_ARG_1_AND_2_ARE_WORDS) {
arg_size += 4;
} else {
arg_size += 2;
}
if (flags & kFLAG_WE_HAVE_A_SCALE) {
arg_size += 2;
} else if (flags & kFLAG_WE_HAVE_AN_X_AND_Y_SCALE) {
arg_size += 4;
} else if (flags & kFLAG_WE_HAVE_A_TWO_BY_TWO) {
arg_size += 8;
}
if (!buffer->Skip(arg_size)) {
return FONT_COMPRESSION_FAILURE();
}
}
if (buffer->offset() - start_offset > std::numeric_limits<uint32_t>::max()) {
return FONT_COMPRESSION_FAILURE();
}
glyph->composite_data_size = buffer->offset() - start_offset;
return true;
}
bool ReadGlyph(const uint8_t* data, size_t len, Glyph* glyph) {
Buffer buffer(data, len);
int16_t num_contours;
if (!buffer.ReadS16(&num_contours)) {
return FONT_COMPRESSION_FAILURE();
}
// Read the bounding box.
if (!buffer.ReadS16(&glyph->x_min) ||
!buffer.ReadS16(&glyph->y_min) ||
!buffer.ReadS16(&glyph->x_max) ||
!buffer.ReadS16(&glyph->y_max)) {
return FONT_COMPRESSION_FAILURE();
}
if (num_contours == 0) {
// Empty glyph.
return true;
}
if (num_contours > 0) {
// Simple glyph.
glyph->contours.resize(num_contours);
// Read the number of points per contour.
uint16_t last_point_index = 0;
for (int i = 0; i < num_contours; ++i) {
uint16_t point_index;
if (!buffer.ReadU16(&point_index)) {
return FONT_COMPRESSION_FAILURE();
}
uint16_t num_points = point_index - last_point_index + (i == 0 ? 1 : 0);
glyph->contours[i].resize(num_points);
last_point_index = point_index;
}
// Read the instructions.
if (!buffer.ReadU16(&glyph->instructions_size)) {
return FONT_COMPRESSION_FAILURE();
}
glyph->instructions_data = data + buffer.offset();
if (!buffer.Skip(glyph->instructions_size)) {
return FONT_COMPRESSION_FAILURE();
}
// Read the run-length coded flags.
std::vector<std::vector<uint8_t> > flags(num_contours);
{
uint8_t flag = 0;
uint8_t flag_repeat = 0;
for (int i = 0; i < num_contours; ++i) {
flags[i].resize(glyph->contours[i].size());
for (size_t j = 0; j < glyph->contours[i].size(); ++j) {
if (flag_repeat == 0) {
if (!buffer.ReadU8(&flag)) {
return FONT_COMPRESSION_FAILURE();
}
if (flag & kFLAG_REPEAT) {
if (!buffer.ReadU8(&flag_repeat)) {
return FONT_COMPRESSION_FAILURE();
}
}
} else {
flag_repeat--;
}
flags[i][j] = flag;
glyph->contours[i][j].on_curve = flag & kFLAG_ONCURVE;
}
}
}
if (!flags.empty() && !flags[0].empty()) {
glyph->overlap_simple_flag_set = (flags[0][0] & kFLAG_OVERLAP_SIMPLE);
}
// Read the x coordinates.
int prev_x = 0;
for (int i = 0; i < num_contours; ++i) {
for (size_t j = 0; j < glyph->contours[i].size(); ++j) {
uint8_t flag = flags[i][j];
if (flag & kFLAG_XSHORT) {
// single byte x-delta coord value
uint8_t x_delta;
if (!buffer.ReadU8(&x_delta)) {
return FONT_COMPRESSION_FAILURE();
}
int sign = (flag & kFLAG_XREPEATSIGN) ? 1 : -1;
glyph->contours[i][j].x = prev_x + sign * x_delta;
} else {
// double byte x-delta coord value
int16_t x_delta = 0;
if (!(flag & kFLAG_XREPEATSIGN)) {
if (!buffer.ReadS16(&x_delta)) {
return FONT_COMPRESSION_FAILURE();
}
}
glyph->contours[i][j].x = prev_x + x_delta;
}
prev_x = glyph->contours[i][j].x;
}
}
// Read the y coordinates.
int prev_y = 0;
for (int i = 0; i < num_contours; ++i) {
for (size_t j = 0; j < glyph->contours[i].size(); ++j) {
uint8_t flag = flags[i][j];
if (flag & kFLAG_YSHORT) {
// single byte y-delta coord value
uint8_t y_delta;
if (!buffer.ReadU8(&y_delta)) {
return FONT_COMPRESSION_FAILURE();
}
int sign = (flag & kFLAG_YREPEATSIGN) ? 1 : -1;
glyph->contours[i][j].y = prev_y + sign * y_delta;
} else {
// double byte y-delta coord value
int16_t y_delta = 0;
if (!(flag & kFLAG_YREPEATSIGN)) {
if (!buffer.ReadS16(&y_delta)) {
return FONT_COMPRESSION_FAILURE();
}
}
glyph->contours[i][j].y = prev_y + y_delta;
}
prev_y = glyph->contours[i][j].y;
}
}
} else if (num_contours == -1) {
// Composite glyph.
if (!ReadCompositeGlyphData(&buffer, glyph)) {
return FONT_COMPRESSION_FAILURE();
}
// Read the instructions.
if (glyph->have_instructions) {
if (!buffer.ReadU16(&glyph->instructions_size)) {
return FONT_COMPRESSION_FAILURE();
}
glyph->instructions_data = data + buffer.offset();
if (!buffer.Skip(glyph->instructions_size)) {
return FONT_COMPRESSION_FAILURE();
}
} else {
glyph->instructions_size = 0;
}
} else {
return FONT_COMPRESSION_FAILURE();
}
return true;
}
namespace {
void StoreBbox(const Glyph& glyph, size_t* offset, uint8_t* dst) {
Store16(glyph.x_min, offset, dst);
Store16(glyph.y_min, offset, dst);
Store16(glyph.x_max, offset, dst);
Store16(glyph.y_max, offset, dst);
}
void StoreInstructions(const Glyph& glyph, size_t* offset, uint8_t* dst) {
Store16(glyph.instructions_size, offset, dst);
StoreBytes(glyph.instructions_data, glyph.instructions_size, offset, dst);
}
bool StoreEndPtsOfContours(const Glyph& glyph, size_t* offset, uint8_t* dst) {
int end_point = -1;
for (const auto& contour : glyph.contours) {
end_point += contour.size();
if (contour.size() > std::numeric_limits<uint16_t>::max() ||
end_point > std::numeric_limits<uint16_t>::max()) {
return FONT_COMPRESSION_FAILURE();
}
Store16(end_point, offset, dst);
}
return true;
}
bool StorePoints(const Glyph& glyph, size_t* offset,
uint8_t* dst, size_t dst_size) {
int previous_flag = -1;
int repeat_count = 0;
int last_x = 0;
int last_y = 0;
size_t x_bytes = 0;
size_t y_bytes = 0;
// Store the flags and calculate the total size of the x and y coordinates.
for (const auto& contour : glyph.contours) {
for (const auto& point : contour) {
int flag = point.on_curve ? kFLAG_ONCURVE : 0;
if (previous_flag == -1 && glyph.overlap_simple_flag_set) {
// First flag needs to have overlap simple bit set.
flag = flag | kFLAG_OVERLAP_SIMPLE;
}
int dx = point.x - last_x;
int dy = point.y - last_y;
if (dx == 0) {
flag |= kFLAG_XREPEATSIGN;
} else if (dx > -256 && dx < 256) {
flag |= kFLAG_XSHORT | (dx > 0 ? kFLAG_XREPEATSIGN : 0);
x_bytes += 1;
} else {
x_bytes += 2;
}
if (dy == 0) {
flag |= kFLAG_YREPEATSIGN;
} else if (dy > -256 && dy < 256) {
flag |= kFLAG_YSHORT | (dy > 0 ? kFLAG_YREPEATSIGN : 0);
y_bytes += 1;
} else {
y_bytes += 2;
}
if (flag == previous_flag && repeat_count != 255) {
dst[*offset - 1] |= kFLAG_REPEAT;
repeat_count++;
} else {
if (repeat_count != 0) {
if (*offset >= dst_size) {
return FONT_COMPRESSION_FAILURE();
}
dst[(*offset)++] = repeat_count;
}
if (*offset >= dst_size) {
return FONT_COMPRESSION_FAILURE();
}
dst[(*offset)++] = flag;
repeat_count = 0;
}
last_x = point.x;
last_y = point.y;
previous_flag = flag;
}
}
if (repeat_count != 0) {
if (*offset >= dst_size) {
return FONT_COMPRESSION_FAILURE();
}
dst[(*offset)++] = repeat_count;
}
if (*offset + x_bytes + y_bytes > dst_size) {
return FONT_COMPRESSION_FAILURE();
}
// Store the x and y coordinates.
size_t x_offset = *offset;
size_t y_offset = *offset + x_bytes;
last_x = 0;
last_y = 0;
for (const auto& contour : glyph.contours) {
for (const auto& point : contour) {
int dx = point.x - last_x;
int dy = point.y - last_y;
if (dx == 0) {
// pass
} else if (dx > -256 && dx < 256) {
dst[x_offset++] = std::abs(dx);
} else {
Store16(dx, &x_offset, dst);
}
if (dy == 0) {
// pass
} else if (dy > -256 && dy < 256) {
dst[y_offset++] = std::abs(dy);
} else {
Store16(dy, &y_offset, dst);
}
last_x += dx;
last_y += dy;
}
}
*offset = y_offset;
return true;
}
} // namespace
bool StoreGlyph(const Glyph& glyph, uint8_t* dst, size_t* dst_size) {
size_t offset = 0;
if (glyph.composite_data_size > 0) {
// Composite glyph.
if (*dst_size < ((10ULL + glyph.composite_data_size) +
((glyph.have_instructions ? 2ULL : 0) +
glyph.instructions_size))) {
return FONT_COMPRESSION_FAILURE();
}
Store16(-1, &offset, dst);
StoreBbox(glyph, &offset, dst);
StoreBytes(glyph.composite_data, glyph.composite_data_size, &offset, dst);
if (glyph.have_instructions) {
StoreInstructions(glyph, &offset, dst);
}
} else if (glyph.contours.size() > 0) {
// Simple glyph.
if (glyph.contours.size() > std::numeric_limits<int16_t>::max()) {
return FONT_COMPRESSION_FAILURE();
}
if (*dst_size < ((12ULL + 2 * glyph.contours.size()) +
glyph.instructions_size)) {
return FONT_COMPRESSION_FAILURE();
}
Store16(glyph.contours.size(), &offset, dst);
StoreBbox(glyph, &offset, dst);
if (!StoreEndPtsOfContours(glyph, &offset, dst)) {
return FONT_COMPRESSION_FAILURE();
}
StoreInstructions(glyph, &offset, dst);
if (!StorePoints(glyph, &offset, dst, *dst_size)) {
return FONT_COMPRESSION_FAILURE();
}
}
*dst_size = offset;
return true;
}
} // namespace woff2
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